Eating too much red meat, butter and other foods that contain high levels of
saturated fats could increase the risk of Alzheimer's, according to a study.

US researchers linked to Harvard University found older women who ate lots of food high in saturated fats had worse memories than others.

By contrast, those who ate more monounsaturated fats - found in olive oil, sunflower oil, seeds, nuts and avocados - had better memories.

Dr Oliva Okereke, from the Brigham and Women's Hospital in Boston, Mass., which is affiliated to Harvard Medical School, said: "When looking at changes in cognitive function, what we found is that the total amount of fat intake did not really matter, but the type of fat did."

She and fellow researchers made their conclusions after looking at results from 6,000 women over 65, who carried out a series of mental tests over four years and answered questionnaires about their diet and lifestyle.

Dr Okereke added: "Substituting in the good fat in place of the bad fat is a fairly simple dietary modification that could help prevent decline in memory."